A. Field Of The Invention
This invention relates primarily to faucets which mix hot and cold water. More particularly, the invention relates to faucets where the temperature of the exiting water is substantially maintained at a preselected temperature, notwithstanding abrupt changes in hot and/or cold water supply pressures.
B. Description Of The Art
A number of types of thermostatic mixing valves which automatically regulate water temperature are well known. For example, see U.S. Pat. Nos. 4,760,953 and 5,148,976. Both of these patents disclose a temperature responsive member which can effect axial movement of a valve member to regulate the proportioning of flow of hot and cold water into a mixing chamber in response to abrupt changes in the temperature of the supplied water and/or the pressure of the supplied water. In the instance of the 4,760,953 patent, valve-forming sleeves are employed in order to improve the performance of the valve. In the 5,148,976 patent, a particular temperature responsive element is utilized. The use of added or special components adds to the cost of a valve, as well as added maintenance costs.
A need exists for an improved thermostatic mixing valve which can be manufactured with fewer parts and still maintain accurate temperature control. A need also exists for a thermostatic valve which is highly responsive.